| Affiliation: | 1.Max Planck Institute for Polymer Research,Mainz,Germany;2.Faculty of Engineering,Hochschule RheinMain,Rüsselsheim,Germany;3.Department of Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE),University Duisburg-Essen,Essen,Germany;4.Deutsches Textiforschungszentrum Nord-West e.V.,Krefeld,Germany |
| Abstract: | To investigate the temperature profiles on laser heated polymer films, we track the thermal radiation with 1 μs time and 1 μm spatial resolution. The resulting two-dimensional temperature graphs are compared to finite element simulations in order to understand the heat conversion and flow. The temperature measurement setup consists of a NIR laser and an optical detection system, which includes high performance optics and a microsecond gated camera, equipped with several interference filters. In this way the thermal radiation is detected in the visible range with spectral resolution. Fitting the spectrum with Planck’s law, two-dimensional micrographs of the temperature distribution are obtained. For polystyrene surfaces we were able to analyze the heating and the ablation behavior. Good agreement was found between experimental results and finite element simulations, when ablation is limited to a few tens of nanometers of the film thickness. Ablation of polystyrene starts at 150°C, 50 K above the glass transition temperature. We suggest a photomechanical ablation mechanism at that threshold fluence. For ablation at higher fluence and peak temperature, experiments indicate a thermal decomposition reaction. The temperature range of spinodal decomposition is not reached and can in our case be ruled out as ablation mechanism. |
